Biomass Data
Data Overview
Data Collections
The following collections are available and freely accessible:
- Biomass Level-1a products
- Biomass Level-1b products
- Biomass Level-1c products
- Biomass Level-2a products
- Biomass Auxiliary products
The following restricted collections are accessible only to the Biomass Mission Internal Users:
The following restricted collections are accessible only to members of Commissioning Team and to the Biomass Mission Internal Users:
- Biomass Level-0 products for the Commissioning Team
- Biomass Level-1a products for the Commissioning Team
- Biomass Level-1b products for the Commissioning Team
- Biomass Level-1c products for the Commissioning Team
- Biomass Level-2a products for the Commissioning Team
- Biomass Auxiliary products for the Commissioning Team
- Biomass Simulated Data
- Biomass Cal/Val
Processing Levels
The Biomass processing suite generates a wide range of products. Data will be processed to the following levels:
- Level-1a/b: At this level, raw data are processed to focused images. This includes processing steps such as compensation of antenna pattern, suppression of RFI artefacts, and the first compensation of ionospheric effects. Ionospheric calibration is key to ensure the quality of Biomass data.
- Level-1c: This level is for generating the interferometric and tomographic image stacks. This includes the co-registration of the images, filtering common Doppler spectrum and phase calibration steps to compensate for residual ionosphere and baseline errors. It also includes computation of the ground steering phase required for subsequent processing levels. Level-1c processing uses the Copernicus Digital Elevation Model (DEM) as input, and will also use the Biomass-derived Digital Terrain Model (DTM) once this is available.
- Level-2a: At this level, intermediate processing will be performed for each image stack.
- Level-2b: Aggregated processing for all Level-2a products for each global cycle over the same location generates a single Level-2b product tile.
- Level-3: This processor is under development and will provide consolidated global biophysical parameters, such as Above Ground Biomass Density and Forest Height. Level-3 products are expected to be delivered after completing the first global cycle.
Product Types
The following products will be included in each of the processing levels:
- Single-look Complex Slant-range (SCS): Level-1a products based on slant-range versus azimuth plane images. Each pixel of the image is represented by a complex value containing calibrated radar amplitude and phase.
- Detected Ground-range Multi-looked (DGM): Level-1b products in the ground-range versus azimuth plane, oriented along ground range and flight direction. Standard products are detected, multi-look products (containing six looks), with square resolution cells and square pixel spacing. DGM products will have a resolution of 50 x 50 m2.
- Co-registered Stack (STA): Level-1c products obtained by co-registering a Level-1a image to a Level-1a reference image. Co-registration involves bi-dimensional interpolation of data over a reference sampling grid. Level-1c products will be very similar to Level-1a products, but will have 3 or 4 polarisations instead.
- Stack-based biophysical product: Level-2a products are biophysical properties. These products will be a biophysical extension of Level-1c stack products. The Level-2a products are geocoded and obtained from a single image stack. There will be three Level-2a products:
- Forest Disturbance: Representing forest change between two global cycles. Areas of deforestation or logging will be marked as zero biomass. The Forest Disturbance product will have a resolution of 50 x 50 m2.
- Forest Height: Representing the top canopy height. The Tomographic and Interferometric and phases are both expected to use the same algorithms for this product, resulting in a three-image stack. The Forest Height product will have a resolution of 200 x 200 m2.
- Ground Notch: Pre-processing product for the Level-2b AGBD product. This product represents ground-cancelled data, which involves applying a signal processing filter on a three-image stack that cancels the signal contribution from the above ground volume layer. The Tomographic and Interferometric and phases are both expected to use the same algorithms for this product, resulting in a three-image stack. The Forest Height product will have a resolution of 200 x 200 m2.
- Tile-based biophysical product: Level-2b products that are biophysical, geocoded, and tile-based. These products are derived from merging all Level-2a products from a Global Cycle. The products can use the Forest Disturbance product availability (from the same geographic tile) or an external (i.e. outside of the Biomass processing) forest mask to mask out non-forest pixels. There will be three Level-2b products:
- Forest Disturbance: Similar to the Level-2a Forest Disturbance product, but combining ascending and descending acquisitions and overlapping areas. These products will also aggregate the probability change map and a computed forest mask. The Forest Disturbance product will have a resolution of 50 x 50 m2.
- Forest Height: Similar to the Level-2a Forest Height product, but combining ascending and descending acquisitions and overlapping areas using weighted averaging and feathering. An aggregated quality indicator is also provided. The Forest Height product will have a resolution of 200 x 200 m2.
- Above Ground Biomass Density (ABGD): This product represents above-ground dry biomass per unit area in tonnes per hectare, and its quality layer in a geographic tile retrieved from the Level-2a Ground Notch product. The ABGD product combines acquisitions from overlapping areas and will have a resolution of 200 x 200 m2.
Product Validation
The validation of Biomass products follows the CEOS Hierarchy of Validation workflow, which is described in the below table:
| Validation Stage | Definition and Current State |
| 0 | No validation. Product accuracy has not been assessed. Product considered beta. |
| 1 | Product accuracy is assessed from a small (typically < 30) set of locations and time periods by comparison with in-situ or other suitable reference data. |
| 2 | Product accuracy is estimated over a significant (typically > 30) set of locations and time periods by comparison with reference in situ or other suitable reference data. Spatial and temporal consistency of the product, and its consistency with similar products, has been evaluated over globally representative locations and time periods. Results are published in the peer-reviewed literature. |
| 3 | Uncertainties in the product and its associated structure are well quantified over a significant (typically > 30) set of locations and time periods representing global conditions by comparison with reference in situ or other suitable reference data. Validation procedures follow community-agreed-upon good practices. Spatial and temporal consistency of the product, and its consistency with similar products, has been evaluated over globally representative locations and time periods. Results are published in the peer-reviewed literature. |
| 4 | Validation results for stage 3 are systematically updated when new product versions are released or as the interannual time series expands. When appropriate for the product, uncertainties in the product are quantified using fiducial reference measurements over a global network of sites and time periods (if available). |
Initially, the goal is to attempt to validate Biomass Level-2A products to CEOS Validation Stage 1, which is challenging due to the lack of high-quality reference data at appropriate scales, particularly in areas of high biomass and/or uncertainty. The recent GEO-TREES initiative has enabled the validation of Biomass products.
Data Quality
Data quality, which includes quality control, performance monitoring, and calibration and validation, is routinely carried out to ensure that Biomass meets its mission and data quality requirements.